Data transmission method and device

Abstract

This application provides a data transmission method and apparatus. The method includes the following: when an access network device receives uplink information from a terminal device through an SDT, the access network device sends a first message. Here, the first message is used to activate a second core network device to stop buffering downlink data of the terminal device, and the access network device receives the downlink data from the second core network device and transmits the downlink data to the terminal device through the SDT. In the above process, when the terminal device activates the SDT, the access network device activates the second core network device to stop or halt buffering of the downlink data of the terminal device, so that the second core network device can transmit the downlink data of the terminal device to the terminal device through the SDT. Therefore, when the terminal device is in an inactive state, the terminal device can directly obtain downlink data without waiting for paging from the network side, thereby improving data transmission efficiency and reducing power consumption of the terminal device.

Description

[Technical Field]

[0001] The present application relates to the field of communication technology, and in particular to a data transmission method and apparatus. [Background technology]

[0002] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority to Chinese Patent Application No. 202211209793.9, entitled "Data Transmission Method and Apparatus," filed with the State Intellectual Property Office of the People's Republic of China on September 30, 2022, which is incorporated herein by reference in its entirety.

[0003] [background] In systems such as new radio (NR) systems, terminal devices in the radio resource control (RRC) idle or inactive state may periodically wake up to monitor paging messages in a discontinuous reception (DRX) scheme. The periodic wakeup cycle is sometimes referred to as the DRX cycle. Paging messages are classified as core network (CN) paging messages and radio access network (RAN) paging messages, which are initiated by core network equipment and access network equipment, respectively. CN paging messages are used to page terminal devices in the idle state, and RAN paging messages are used to page terminal devices in the inactive state.

[0004] The network side can configure different DRX cycles for different types of paging messages. Therefore, the DRX used to monitor CN paging messages is sometimes called idle DRX, and the DRX used to monitor RAN paging messages is sometimes called inactive DRX. To further reduce power consumption, the DRX cycle can be extended. In other words, the terminal device periodically wakes up to monitor paging messages by using an extended discontinuous reception (eDRX) cycle. The duration of the inactive eDRX cycle can exceed 10.24 seconds, allowing the terminal device to enter a sleep state for a longer period.

[0005] During the sleep period of the terminal device, the network side buffers data that needs to be transmitted to the terminal device. However, the longer the sleep time of the terminal device, the larger the amount of data that needs to be buffered on the network side. In one implementation, when the terminal device is in an RRC inactive state, the network side may page the terminal device to cause the terminal device to switch to an RRC connected state, so as to cause the terminal device to transmit data. When the data transmission is completed, the terminal device switches back to an RRC inactive state.

[0006] In the above-mentioned data transmission process, the terminal equipment needs to perform state switching, which increases the amount of signaling exchanged with the network side and increases the power consumption of the terminal equipment. Summary of the Invention

[0007] The present application provides a data transmission method and apparatus for improving the data transmission efficiency of a terminal device in an RRC inactive state and reducing the power consumption of the terminal device.

[0008] According to a first aspect, the present application provides a data transmission method. The method is applicable to a scenario in which a terminal device in an RRC inactive state performs information transmission by using a small data transmission process. The method is executed by access network equipment or a module within the access network equipment. This specification describes an example in which the method is executed by the access network equipment. The method includes: the access network equipment receiving uplink information from the terminal device through a small data transmission (SDT), where the resource used for transmitting the uplink information is a random access resource or a configured granted resource used for the SDT; and the access network equipment transmitting a first message, where the first message is used to activate a second core network equipment to stop buffering downlink data of the terminal device. The access network equipment receives the downlink data from the second core network equipment and transmits the downlink data to the terminal device through the SDT.

[0009] In the above process, when the terminal device activates the SDT, the access network device can activate the second core network device to stop or halt buffering of the downlink data of the terminal device, so that the second core network device can transmit the downlink data of the terminal device to the terminal device through the SDT. Therefore, when the terminal device is in an inactive state, the terminal device can directly obtain the downlink data without waiting for paging from the network side, thereby improving data transmission efficiency and reducing the power consumption of the terminal device.

[0010] In one implementation, the access network equipment holds the context of the terminal equipment, or the device sending the first message is the access network equipment holding the context of the terminal equipment.

[0011] In one implementation, the method further includes: obtaining a context of the terminal device;

[0012] In one implementation, the method further includes, after determining that the SDT is completed, transmitting a second message by the access network equipment, where the second message is used to activate a second core network equipment to buffer downlink data of the terminal equipment, or the second message indicates a period duration of an extended discontinuous reception period for monitoring, by the terminal equipment in an inactive state, for paging messages initiated by the radio access network.

[0013] In one implementation, the access network equipment determining that the SDT is complete includes: if the access network equipment receives a null data packet or a data packet in a pre-configured format, the access network equipment determines that the SDT is complete.

[0014] In one implementation, the access network device determining that the SDT has completed includes: upon receiving first uplink information from the terminal device or first downlink data from the second core network device, the access network device starts a timer, where the timer has a preset time duration; and upon expiration of the timer, if the access network device does not receive second uplink information from the terminal device or second downlink data from the second core network device, the access network device determines that the SDT has completed.

[0015] In one implementation, the method further includes: the access network equipment sending a third message to the terminal equipment, where the third message indicates that the terminal equipment transitions to an inactive state.

[0016] In one implementation, the method further includes: the access network device releases the terminal device to an inactive state, and retains, for the terminal device, a context of the terminal device and a connection to the first core network device associated with the terminal device.

[0017] In one implementation, the method further includes receiving a first response message to the first message, where the first response message is used to confirm that the second core network device is activated to stop or halt buffering of downlink data of the terminal device, or the first response message is used to confirm that data transmission can be performed between the terminal device and the access network.

[0018] In one implementation, the method further includes: sending a sixth message, where the sixth message is used to activate the second core network device to start buffering downlink data of the terminal device.

[0019] In one implementation, the access network equipment is the access network equipment to which the cell to which the terminal equipment is currently camped belongs.

[0020] According to a second aspect, the present application provides a data transmission method. The method is applicable to a scenario in which a terminal device in an RRC inactive state performs information transmission by using a small data process. The method is executed by a first core network device or a module in the first core network device. This specification describes an example in which the method is executed by the first core network device. The method includes: the first core network device receiving a first message from an access network device, where the first message is used to activate a second core network device to stop buffering downlink data of the terminal device; and the first core network device sending a fourth message to the second core network device based on the first message, where the fourth message instructs the second core network device to stop buffering downlink data of the terminal device or indicates that data transmission can be performed between the terminal device and the access network.

[0021] In one implementation, the method further includes receiving a sixth message from the access network equipment, where the sixth message is used to activate the second core network equipment to start buffering downlink data of the terminal equipment, and sending a seventh message to the second core network equipment based on the sixth message, where the seventh message instructs the second core network equipment to start buffering downlink data of the terminal equipment or indicates that data transmission cannot be performed between the terminal equipment and the access network.

[0022] According to a third aspect, the present application provides a data transmission method. This method is applicable to a scenario in which a terminal device in an RRC inactive state performs information transmission by using a small data process. The method is executed by a second core network device or a module in the second core network device. This specification describes an example in which the method is executed by the second core network device. The method includes: the second core network device receiving a fourth message from the first core network device, where the fourth message instructs the second core network device to stop buffering downlink data of the terminal device, or the fourth message indicates that data transmission can be performed between the terminal device and the access network. Based on the fourth message, the second core network device stops buffering the downlink data of the terminal device and transmits the downlink data of the terminal device to the access network device.

[0023] In one implementation, the access network equipment holds the context of the terminal equipment, or the access network equipment is a device that holds the context of the terminal equipment.

[0024] In one implementation, the method further includes receiving a seventh message from the first core network device, where the seventh message indicates to start buffering downlink data of the terminal device, or the seventh message indicates that data transmission cannot be performed between the terminal device and the access network.

[0025] According to a fourth aspect, the present application provides a data transmission method. The method is applicable to a scenario in which a terminal device in an RRC inactive state performs information transmission by using a small data process. The method is executed by an access network device or a module in the access network device. This specification describes an example in which the method is executed by the access network device. The method includes: after determining that the small data transmission SDT of the terminal device is completed, the access network device generates a second message; and the access network device sends the second message to a first core network device. Here, the second message is used to activate the second core network device to buffer downlink data of the terminal device.

[0026] In the above-mentioned process, when it determines that the SDT of the terminal equipment is completed, the access network equipment can activate the second core network equipment to buffer the downlink data of the terminal equipment, so that when the terminal equipment is in an inactive state, the buffering of data from the network side is performed on the network side, reducing the number of times the network side pages the terminal equipment and reducing the power consumption of the terminal equipment.

[0027] In one implementation, the access network equipment determining that the small data transmission SDT of the terminal equipment is completed includes: If the access network equipment receives a null data packet or a data packet in a pre-configured format, the access network equipment shall determine that the SDT is complete.

[0028] In one implementation, the access network equipment determining that the small data transmission SDT of the terminal equipment is completed includes: Upon receiving first uplink information from the terminal device or first downlink data from the second core network device, the access network device starts a timer, where the timer has a preset time duration, and upon expiration of the timer, if the access network device does not receive second uplink information from the terminal device or second downlink data from the second core network device, the access network device determines that the SDT has completed.

[0029] In one implementation, the method further includes: the access network equipment sending a third message to the terminal equipment, where the third message indicates that the terminal equipment transitions to an inactive state.

[0030] In one implementation, the access network equipment maintains the context of the terminal equipment.

[0031] According to a fifth aspect, the present application provides a data transmission method. The method is applicable to a scenario in which a terminal device in an RRC inactive state performs information transmission by using a small data process. The method is executed by a first core network device or a module in the first core network device. This specification describes an example in which the method is executed by the first core network device. The method includes: the first core network device receiving a second message from an access network device, where the second message is used to activate a second core network device to buffer downlink data of the terminal device; and the first core network device sending a fifth message to the second core network device based on the second message, where the fifth message instructs the second core network device to buffer downlink data of the terminal device or indicates that the terminal device will transition to an inactive state.

[0032] According to a sixth aspect, the present application provides a data transmission method. The method is applicable to a scenario in which a terminal device in an RRC inactive state performs information transmission by using a small data process. The method is executed by a second core network device or a module in the second core network device. This specification describes an example in which the method is executed by the second core network device. The method includes: the second core network device receiving a fifth message from the first core network device, where the fifth message instructs the second core network device to buffer downlink data of the terminal device, or the fifth message indicates that the terminal device will transition to an inactive state. The second core network device buffers the downlink data of the terminal device based on the fifth message.

[0033] According to a seventh aspect, the present application provides a data transmission method. This method is applicable to a scenario in which a terminal device in an RRC inactive state performs information transmission by using a small data process. The method is executed by a second core network device or a module in the second core network device. This specification describes an example in which the method is executed by the second core network device. The method includes: the second core network device receives uplink information from the terminal device through a small data transmission (SDT), and sends a buffering release request message to the first core network device. The buffering release request message is used to request the terminal device to stop buffering downlink data. The second core network device stops buffering the downlink data of the terminal device and sends the buffered downlink data to the terminal device through the SDT.

[0034] In the above process, when the terminal device activates the SDT, the second core network device determines that the terminal device can perform data transmission, stops or releases the buffering of downlink data of the terminal device, and transmits the downlink data to the terminal device through the SDT. Therefore, when the terminal device is in an inactive state, the terminal device can directly obtain downlink data without waiting for paging from the network side, thereby improving data transmission efficiency and reducing the power consumption of the terminal device.

[0035] In one implementation, the method further includes: the second core network device receiving a buffering release response message from the first core network device, where the buffering release response message is used to respond to the buffering release request message.

[0036] In one implementation, the method further includes: after determining that the SDT is completed, the second core network device buffers downlink data of the terminal device.

[0037] In one implementation, the method further includes: the second core network device sending a buffering enable request message to the first core network device, where the buffering enable request message indicates a request for buffering downlink data of the terminal device.

[0038] In one implementation, the second core network device determining that the SDT is completed includes: when the second core network device receives a null data packet or a data packet in a preset format, the second core network device determines that the SDT is completed.

[0039] In one implementation, the second core network device determining that the SDT has completed includes: upon receiving first uplink information from the terminal device, the second core network device starts a timer, where the timer has a preset time duration; upon expiration of the timer, if the second core network device does not receive second uplink information from the terminal device, the second core network device determines that the SDT has completed.

[0040] According to an eighth aspect, the present application provides a data transmission method. The method is applicable to a scenario in which a terminal device in an RRC inactive state performs information transmission by using a small data process. The method is executed by a second core network device or a module in the second core network device. This specification describes an example in which the method is executed by the second core network device. The method includes: after determining that the small data transmission SDT of the terminal device is completed, the second core network device sends a buffering enable request message to the first core network device. The buffering enable request message is used to request buffering of downlink data of the terminal device. The second core network device receives a buffering release confirmation message from the first core network device and buffers the downlink data of the terminal device.

[0041] In the above-mentioned process, when it is determined that the SDT of the terminal device is completed, the second core network device can actively buffer the downlink data of the terminal device, so that when the terminal device is in an inactive state, data from the network side is buffered on the network side, reducing the number of times the network side pages the terminal device and reducing the power consumption of the terminal device.

[0042] In one implementation, the second core network device determining that the SDT of the terminal device is completed includes: if the second core network device receives a null data packet or a data packet in a preset format, the second core network device determines that the SDT is completed.

[0043] In one implementation, the second core network device determining that the SDT of the terminal device has completed includes: upon receiving first uplink information from the terminal device, the second core network device starts a timer, where the timer's time duration is a preset duration; upon expiration of the timer, if the second core network device does not receive second uplink information from the terminal device, the second core network device determines that the SDT has completed.

[0044] According to a ninth aspect, the present application further provides a communication device, which performs any of the methods provided in any one of the first to eighth aspects. The communication device may be implemented by hardware, or by hardware executing corresponding software. The hardware or software may include one or more units or modules corresponding to the above-mentioned functions.

[0045] In a possible implementation, the communication device includes a processor configured to support the communication device in performing the corresponding functions of the network equipment in the above-described methods. The communication device may further include a memory coupled to the processor, the memory storing program instructions and data required by the communication device. Optionally, the communication device may further include an interface circuit configured to support communication between the communication device and a device such as a terminal device.

[0046] In a possible implementation, the communication device includes corresponding functional modules configured to perform the steps of the above-described methods. The functions may be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-described functions.

[0047] In a possible implementation, the communication device includes corresponding functional modules configured to perform the steps of the above-described methods. The functions may be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above-described functions.

[0048] In a possible implementation, the communication device includes a processing unit and a communication unit, which may perform the corresponding functions in the above-described method examples. For details, please refer to the descriptions in the methods provided in the first to eighth aspects. Details will not be described in this specification.

[0049] According to a tenth aspect, there is provided a communication device, the communication device including a processor and an interface circuit, the interface circuit configured to receive a signal from a communication device other than the communication device and transmit the signal to the processor, or transmit a signal from the processor to a communication device other than the communication device, the processor configured to implement a method according to any one of the first to eighth aspects and any possible implementation of any one of the first to eighth aspects by using logic circuits or by executing code instructions.

[0050] According to an eleventh aspect, there is provided a communication device, the communication device including a processor and an interface circuit, the interface circuit configured to receive a signal from a communication device other than the communication device and transmit the signal to the processor, or to transmit a signal from the processor to a communication device other than the communication device, the processor configured to implement functional modules of a method according to any one of the first to eighth aspects and any possible implementation of any one of the first to eighth aspects by using logic circuits or by executing code instructions.

[0051] According to a twelfth aspect, there is provided a computer-readable storage medium storing a computer program or instructions which, when executed by a processor, implements a method according to any one of the first to eighth aspects, and any possible implementation of any one of the first to eighth aspects.

[0052] According to a thirteenth aspect, there is provided a computer program product storing instructions which, when executed by a processor, implement a method according to any one of the first to eighth aspects, and any possible implementation of any one of the first to eighth aspects.

[0053] According to a fourteenth aspect, there is provided a chip system. The chip system includes a processor and may further include a memory configured to implement a method according to any one of the first to eighth aspects and any possible implementation of any one of the first to eighth aspects. The chip system may include a chip, or may include a chip and other discrete components.

[0054] According to a fifteenth aspect, there is provided a communications system, the system comprising an apparatus configured to perform the method provided in the first aspect, an apparatus configured to perform the method provided in the second aspect, and an apparatus configured to perform the method provided in the third aspect.

[0055] According to a sixteenth aspect, there is provided a communications system, the system comprising an apparatus configured to perform the method provided in the fourth aspect, an apparatus configured to perform the method provided in the fifth aspect, and an apparatus configured to perform the method provided in the sixth aspect. [Brief explanation of the drawings]

[0056] [Figure 1] FIG. 1 illustrates a network architecture applicable to embodiments of the present application. [Figure 2] FIG. 1 illustrates an SDT procedure according to an embodiment of the present application. [Figure 3] FIG. 1 illustrates an SDT procedure according to an embodiment of the present application. [Figure 4] 1 is a schematic flow chart illustrating a data transmission method according to an embodiment of the present application; [Figure 5] 1 is a schematic flow chart illustrating a data transmission method according to an embodiment of the present application; [Figure 6] 1 is a schematic flowchart illustrating a data transmission method according to an embodiment of the present application; [Figure 7] 1 is a schematic flow chart illustrating a data transmission method according to an embodiment of the present application; [Figure 8] 1 is a schematic flow chart illustrating a data transmission method according to an embodiment of the present application; [Figure 9] 1 is a schematic flow chart illustrating a data transmission method according to an embodiment of the present application; [Figure 10] 1 is a schematic flow chart illustrating a data transmission method according to an embodiment of the present application; [Figure 11]1 is a schematic flow chart illustrating a data transmission method according to an embodiment of the present application; [Figure 12] 1 is a diagram illustrating a configuration of a communication device according to an embodiment of the present application. [Figure 13] 1 is a diagram illustrating a configuration of a communication device according to an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0057] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present application are described in detail below with reference to the accompanying drawings of the present application.

[0058] The technical solutions in the embodiments of the present application may be applied to various communication systems, such as a long term evolution (LTE) system, a new radio (NR) system, or other communication systems such as future communication systems, which are not particularly limited herein.

[0059] In order to facilitate understanding of the embodiments of the present application, application scenarios of the present application are described below. The network architectures and service scenarios described in the embodiments of the present application are intended to more clearly explain the technical solutions in the embodiments of the present application, and do not constitute any constraints on the technical solutions provided in the embodiments of the present application. Those skilled in the art may recognize that when new service scenarios emerge, the technical solutions provided in the embodiments of the present application can also be applied to similar technical problems.

[0060] In an embodiment of the present application, the terminal equipment is a device having a wireless transceiver function or a chip that may be disposed within the device. A device having a wireless transceiver function may also be referred to as a user equipment (UE), access terminal, subscriber unit, subscriber station, mobile station, remote station, remote terminal, mobile device, user terminal, user agent, or user device. In practical applications, the terminal equipment in the embodiment of the present application may be a mobile phone, a tablet computer (Pad), a computer with a wireless transceiver function, a virtual reality (VR) terminal, an augmented reality (AR) terminal, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical care, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, or the like. In the embodiment of the present application, the application scenario is not limited. In this application, the above-mentioned devices having radio transceiver functionality, and chips that may be located within the devices, are collectively referred to as terminal equipment.

[0061] In embodiments of the present application, the access network equipment may be radio access equipment in various standards, and the access network equipment may also be referred to as a radio access network (RAN) device. For example, the access network equipment may be a next generation NodeB (gNB) in an NR system, or an evolved NodeB (eNB), a radio network controller (RNC) or NodeB (NodeB, NB), a base station controller (BSC), a base transceiver station (BTS), a home NodeB (e.g., home evolved NodeB or home NodeB, HNB), a baseband unit (BBU), an access point (AP), a wireless relay node, a wireless backhaul node, a transmission and reception point (TRP or TP) in a wireless fidelity (Wi-Fi) system, or the like. Alternatively, the access network equipment may be a gNB or a transmission point (TRP or TP) in a 5G (NR) system, or an antenna panel or a group of antenna panels (including multiple antenna panels) of a base station in a 5G system. Alternatively, the access network equipment may be a network node constituting a gNB or a transmission point, such as a baseband unit (BBU) or a DU in a central unit-distributed (CU-DU) architecture.

[0062] To facilitate understanding of the embodiments of the present application, a communication system applicable to the embodiments of the present application will first be described in detail using the communication system shown in Fig. 1 as an example. Fig. 1 is a diagram illustrating a communication system applicable to the embodiments of the present application. As shown in Fig. 1, the communication system includes the following devices or network elements: A session management function (SMF) may be configured to perform functions such as session management (including session establishment, modification, and deletion management) in a mobile network.

[0063] A user plane function (UPF) is a functional network element of the user plane, and its main functions include packet routing and forwarding, Quality of Service (QoS) processing of user plane data, and the like.

[0064] The main functions of the access and mobility management function (AMF) include termination point of the radio access network control plane, termination point of non-access signaling, mobility management, access authorization or authentication, and the like.

[0065] The policy control function (PCF) is primarily responsible for functions such as establishing, releasing, and modifying user plane transmission paths.

[0066] A data network (DN) may be a network that provides services to terminal equipment. For example, some DNs may provide Internet access to terminal equipment.

[0067] The above is just an example, and the communication system may further include other devices or network elements, and these examples will not be described one by one here.

[0068] The terminal device may perform data transmission in an inactive state by using small data transmission (SDT) techniques to reduce signaling transmission and power consumption of the terminal device. SDT can be classified into random access (RA)-based SDT and Type 1 configured grant (CG)-based SDT. Based on the location of the UE context, RA-based SDT can be classified into RA-based SDT without UE context relocation (RA-based SDT without UE context relocation) and RA-based SDT with UE context relocation (RA-based SDT with UE context relocation).

[0069] In the RA-based SDT procedure, the first access network equipment that transitions the terminal device from the connected state to the inactive state and the second access network equipment used when the terminal device initiates SDT may be different access network equipment. In this application, the first access network equipment releases the terminal device to the inactive state and retains, for the terminal device, the terminal device's context and the connection to the first core network equipment associated with the terminal device. In other words, the first access network equipment is the access network equipment that last provided service to the terminal device before the terminal device became inactive (last serving gNB), and may also be referred to as the anchor access network equipment. The second access network equipment is the access network equipment to which the cell on which the terminal device is currently camped belongs, and may also be referred to as the new access network equipment (new gNB) or the receiving access network equipment (receiving gNB).

[0070] Figure 2 illustrates an SDT procedure according to the present application. Figure 2 illustrates an RA-based SDT procedure without UE context relocation. In other words, in the SDT procedure, the anchor access network device does not perform the transition.

[0071] Step 201: The terminal device sends an RRC resumption request and uplink information to a second access network device.

[0072] Before performing the SDT procedure, the terminal device is in an inactive state. The RRC resume request includes information such as an inactive radio network temporary identifier (I-RNTI) and a cause value. The uplink information includes at least one of uplink data and uplink signaling.

[0073] Step 202: The second access network device determines the first access network device based on the I-RNTI, and sends a terminal device context resume request message to the first access network device.

[0074] The terminal device context resume request message is used to acquire the context of the terminal or to request the first access network device to perform data transmission or small data transmission. The terminal device context resume request message includes information such as an I-RNTI.

[0075] Optionally, the terminal device context resume request message further includes a small data transmission indication (SDT indication), or the terminal device context resume request message and the small data transmission indication (SDT indication) are both sent to the first access network device.

[0076] In this process, the first access network equipment decides not to perform anchor relocation, thereby being able to preserve the context of the terminal equipment.

[0077] Step 203: The first access network device sends a terminal device partial context transfer message to the second access network device.

[0078] The terminal device partial context transfer message includes a terminal device partial context (UE partial context), which may be a radio link control (RLC) partial context, so that the first access network device maintains a PDCP entity and the second access network device establishes an RLC entity corresponding to the SDT.

[0079] Step 204: The second access network device sends a terminal device partial context confirmation message to the first access network device.

[0080] Step 205: The second access network device sends the uplink information of the terminal device to the first access network device.

[0081] Step 206: The first access network device forwards the uplink information to the UPF device. The specific process is not described.

[0082] Optionally, when the terminal device needs to transmit further uplink data, the terminal device may transmit the uplink data to a second access network device, which transmits the uplink data to the first access network device, and the first access network device forwards the uplink data to the UPF device.

[0083] Step 207: After the terminal equipment completes sending the uplink information, the first access network equipment sends a terminal equipment context resume failure message to the second access network equipment.

[0084] The terminal device context resume failure message includes an RRC release message, which instructs the terminal device to release the RRC connection.

[0085] Step 208: The second access network device sends an RRC release message to the terminal device.

[0086] After receiving the RRC release message, the terminal device continues to remain in an inactive state.

[0087] The above process is an RA-based SDT procedure without UE context relocation. The RA-based SDT procedure with UE context relocation is described below. In other words, in the SDT procedure, the anchor access network device performs the transition.

[0088] 3 is a diagram illustrating the SDT procedure according to the present application. Before performing the SDT procedure, the terminal equipment is in an inactive state.

[0089] Step 301: A terminal device sends an RRC resumption request and uplink information to a second access network device.

[0090] Step 302: The second access network device determines the first access network device based on the I-RNTI, and sends a terminal device context resume request message to the first access network device.

[0091] Steps 301 and 302 are the same as steps 201 and 202 in FIG. 2, and the details will not be explained again.

[0092] In this process, the first access network device decides to perform anchor relocation to transfer the context of the terminal device to the second access network device.

[0093] Step 303: The first access network device sends a terminal device context resume response message to the second access network device.

[0094] The terminal device context resume response message includes the entire context of the terminal device.

[0095] Step 304: The second access network device forwards the uplink information of the terminal device to the UPF device.

[0096] The second access network device forwards the uplink information to the UPF device, and the specific process is not described.

[0097] Optionally, step 305: the second access network device sends an address indication (Xn-U address indication) of the second access network device to the first access network device, where the address indication indicates a tunnel address for forwarding downlink data of the terminal device.

[0098] The sending of the address indication can prevent the loss of buffered downlink data in the first access network equipment.

[0099] Step 306: The second access network device sends a path switch request message to the first access network device.

[0100] Step 307: The first access network device sends a path switch request confirmation message to the second access network device.

[0101] A data forwarding path between the first access network device and the second access network device is established by using steps 306 and 307. Then, the second access network device transmits the uplink data buffered before step 307 to the first access network device, the first access network device transmits the uplink data to the core network, and the first access network device can transmit the downlink data received from the core network to the terminal device via the second access network device.

[0102] Optionally, step 308: if the terminal equipment further needs to send uplink data, the terminal equipment may send the uplink data to the second access network equipment.

[0103] Step 309: The second access network device directly forwards the uplink data from the terminal device to the UPF device.

[0104] Step 310: After the terminal equipment completes sending the uplink information, the second access network equipment sends an RRC release message to the terminal equipment.

[0105] After receiving the RRC release message, the terminal device continues to remain in an inactive state.

[0106] In the SDT procedure in Figures 2 and 3, if the duration of the eDRX period configured by the network side for the terminal equipment and used for monitoring RAN paging messages exceeds 10.24 seconds and the terminal equipment is in an inactive state, the network side configures the SMF or UPF to buffer downlink data that needs to be sent to the terminal equipment, so that the downlink data cannot be forwarded to the terminal equipment in the SDT procedure.

[0107] Therefore, the present application provides a method: when the cycle duration of the inactive eDRX cycle of the terminal device exceeds 10.24 seconds, the terminal device uses the SDT procedure to simultaneously transmit uplink information and downlink data, thereby improving the data transmission efficiency of the terminal device in the RRC inactive state and reducing the power consumption of the terminal device.

[0108] This application can be applied to an SDT procedure, in which the access network equipment activates the core network equipment to stop buffering the downlink data of the terminal equipment, so that the core network equipment forwards the downlink data of the terminal equipment to the terminal equipment through the SDT. Different embodiments will be described separately below. The core network equipment may be a UPF or an SMF. The access network equipment may be an anchor access network equipment or a new access network equipment. For ease of description, this application will refer to the anchor access network equipment as the first access network equipment and the new access network equipment as the second access network equipment.

[0109] The message names in the following procedures in this application are merely examples. In actual applications, the message names may be changed. In addition, the message names are not limited in this application.

[0110] 4 is a schematic flowchart illustrating a data transmission method according to an embodiment of the present application. In the steps of this method, the access network equipment may be an anchor access network equipment or a new access network equipment.

[0111] Optionally, before step 401, there may be further steps:

[0112] The access network equipment sends a sixth message to the first core network equipment. Here, the sixth message is used to activate a second core network equipment (e.g., SMF or UPF) to start buffering downlink data of the terminal equipment, or the sixth message indicates that data transmission cannot be performed between the terminal equipment and the access network. For example, the access network equipment may be a device such as a base station, and the first core network equipment may be a device such as an AMF. The name of the sixth message is not limited. For example, the sixth message may be a mobile terminated (MT) communication handling request message.

[0113] The first core network device sends a seventh message to the second core network device. Here, the seventh message instructs the second core network device to start buffering downlink data of the terminal device, or the seventh message indicates that data transmission cannot be performed between the terminal device and the access network. This is not limited in the present application. The seventh message can be determined based on the sixth message. For example, the second core network device is an SMF, and the name of the seventh message is not limited. For example, the seventh message can be an Nsmf_PDUSession_UpdateSMContextRequest message.

[0114] The second core network device starts buffering downlink data of the terminal device based on the seventh message, or determines that data transmission cannot be performed between the terminal device and the access network.

[0115] Step 401: A terminal device sends uplink information to an access network device through an SDT, and in response, the access network device receives uplink information from the terminal device through an SDT.

[0116] In one implementation, before step 401, the terminal device is in an inactive state, and the duration of the eDRX period configured by the network side for the terminal device, which is used for monitoring RAN paging messages, exceeds 10.24 seconds. The specific process by which the terminal device starts the SDT is not limited in this application. The terminal device may further send an RRC resumption request to the access network device. The specific content included in the RRC resumption request is not limited in this application.

[0117] In one implementation, the terminal device may send the RRC resumption request and uplink information by using message 3 in a four-phase random access procedure or message A in a two-phase random access procedure.

[0118] In this application, the uplink information includes at least one of uplink data and uplink signaling. The uplink data may be referred to as uplink small data. In other words, the total amount of uplink data to be transmitted is less than a preconfigured threshold. The uplink data is data that can be directly transmitted by a terminal device in an inactive state.

[0119] In one implementation, the SDT may be a configured grant-based SDT or a random access-based SDT. If the SDT is a configured grant-based SDT, the resources used to transmit uplink information are the configured grant resources used for the SDT. Alternatively, if the SDT is a random access-based SDT, the resources used to transmit uplink information are the random access resources used for the SDT.

[0120] In this application, the access network equipment is a device that holds the context of the terminal equipment. For example, in a first possible scenario, the access network equipment is a first access network equipment (i.e., anchor access network equipment). In this scenario, when a second access network equipment requests to obtain the context of the terminal equipment from the first access network equipment, the first access network equipment decides not to perform anchor relocation and holds the context of the terminal equipment. In this scenario, the terminal equipment first sends uplink information to the second access network equipment, and then the second access network equipment forwards the uplink information to the first access network equipment.

[0121] In a second possible scenario, the access network device is a second access network device (i.e., a new access network device). In this scenario, when the second access network device requests to obtain the terminal device's context from the first access network device, the first access network device decides to perform anchor relocation and transfer the entire terminal device's context to the second access network device. In this scenario, the access network device may obtain uplink information directly from the terminal device.

[0122] Step 402: The access network device sends a first message to a first core network device, and in response, the first core network device receives the first message from the access network device.

[0123] The first message is used to activate the second core network equipment to stop or halt buffering of downlink data of the terminal equipment, or the first message indicates that data transmission can be performed between the terminal equipment and the access network, or the first message instructs the second core network equipment to stop or halt buffering of downlink data of the terminal equipment.

[0124] In one implementation, the first core network device is an AMF, and the second core network device is a UPF or an SMF.

[0125] In one implementation, the message type of the first message is an N2 message, and the N2 message may be extended based on an existing message. For example, the N2 message may be an RRC INACTIVE TRANSITION REPORT message, or the N2 message may be a newly defined message. This is not limited in the present application.

[0126] In a first possible scenario, if the access network device is an anchor access network device, steps 202 to 204 are further included before step 402. For details, please refer to the procedure shown in Figure 2. The details will not be described again in this specification.

[0127] In a second possible scenario, if the access network equipment is a new access network equipment, step 302 and step 303 are further included before step 402. For details, please refer to the procedure shown in Figure 3, which will not be described again in this specification.

[0128] Step 403: The first core network device sends a fourth message to the second core network device based on the first message, and in response, the second core network device receives the fourth message from the first core network device.

[0129] The fourth message instructs the second core network device to stop or discontinue buffering the downlink data of the terminal device, or indicates that data transmission can be performed between the terminal device and the access network. Alternatively, the fourth message is used to deliver new rules to the second core network device, for example, the new rules indicating that the second core network device no longer needs to buffer the downlink data of the terminal device.

[0130] The specific name of the fourth message is not limited. For example, the fourth message may be a protocol data unit (PDU) session update session modification context request message. The fourth message may further indicate that the SMF may update a PDU session associated with the terminal device.

[0131] Implementation 1: When the first core network device is an AMF and the second core network device is an SMF, the AMF may directly send the fourth message to the SMF, and the SMF may further send a response message to the AMF. For example, the response message is a PDU session update session change context response message.

[0132] Implementation 2: If the first core network device is an AMF and the second core network device is a UPF, please refer to the procedure in Figure 5.

[0133] Step 501: The AMF sends a fourth message to the SMF, where the fourth message is a PDU session update session change context request message.

[0134] In one implementation, the SMF may forward the fourth message to the UPF. In another implementation, the SMF may generate a new message based on the fourth message and forward the generated message to the UPF. Step 502 illustrates an example.

[0135] Step 502: The SMF sends an N4 session modification message to the UPF based on the fourth message.

[0136] The N4 session modification message instructs the second core network device to stop or discontinue buffering the terminal device's downlink data, the N4 session modification message indicates that data transmission can be performed between the terminal device and the access network, or the N4 session modification message is used to deliver new rules to the UPF, for example, the new rules indicate that the UPF no longer needs to buffer the terminal device's downlink data.

[0137] Step 503: The SMF sends a response message to the AMF. For example, the response message is a PDU session update session change context response message.

[0138] In the above procedure, the AMF instructs the UPF via the SMF not to buffer the downlink data of the terminal equipment, so that the UPF can transmit the downlink data of the terminal equipment through the SDT.

[0139] Optionally, step 404: The first core network device sends a first response message of the first message to the access network device.

[0140] The first response message is used to confirm that the second core network device has been activated to stop or halt buffering of downlink data of the terminal device, or the first response message is used to confirm that data transmission can be performed between the terminal device and the access network.

[0141] In one implementation, when the first core network device receives the response message from the second core network device, a first response message may be sent by the first core network device.

[0142] In the present application, after receiving the fourth message, the second core network device may stop buffering the downlink data of the terminal device based on the fourth message. After the second core network device determines not to buffer the downlink data of the terminal device, if the second core network device receives the downlink data of the terminal device, the second core network device needs to forward the downlink data of the terminal device to the terminal device.

[0143] Optionally, when the second core network device buffers the downlink data of the terminal device, the second core network device may transmit the downlink data of the terminal device through the SDT. For example, the second core network device may perform the following steps:

[0144] Step 405: The second core network equipment sends downlink data of the terminal equipment to the access network equipment, and in response, the access network equipment receives the downlink data from the second core network equipment.

[0145] Step 406: The access network device sends the downlink data to the terminal device through the SDT.

[0146] Optionally, the access network equipment may further receive uplink small data from the terminal equipment and forward the uplink small data to the UPF.

[0147] After the SDT of the terminal equipment is completed, the access network equipment may instruct the terminal equipment to transition to an inactive state, as described in detail below.

[0148] Optionally, step 407: the access network equipment sends a third message to the terminal equipment, where the third message indicates that the terminal equipment transitions to an inactive state.

[0149] In one implementation, the third message may be an RRC release message. Upon receiving the third message, the terminal device transitions to the inactive state again.

[0150] In the above process, when the terminal device activates the SDT, the access network device activates the second core network device to stop or halt buffering of the downlink data of the terminal device, so that the second core network device can transmit the downlink data of the terminal device to the terminal device through the SDT. Therefore, when the terminal device is in an inactive state, the terminal device can directly obtain the downlink data without waiting for paging from the network side, thereby improving data transmission efficiency and reducing the power consumption of the terminal device.

[0151] In this application, after the SDT is completed, the access network equipment may activate the second core network equipment to buffer the downlink data of the terminal equipment, to prevent the terminal equipment in an inactive state from being woken up frequently, as will be described in detail below.

[0152] 6 is a schematic flowchart illustrating a data transmission method according to an embodiment of the present invention. In this method procedure, the access network equipment may be an anchor access network equipment or a new access network equipment. The method procedure shown in FIG. 6 may be implemented in combination with the method procedure shown in FIG. 4, or may be implemented separately, which is not limited in this application.

[0153] Step 601: After determining that the SDT of the terminal equipment is completed, the access network equipment generates a second message.

[0154] The access network equipment maintains the context of the terminal equipment, for details please refer to the above description, and the details will not be repeated here.

[0155] In one implementation, the second message is a message type N2 message, and is used to activate a second core network device to buffer downlink data for the terminal device, or indicates a period duration of an eDRX period for monitoring paging messages initiated by the radio access network by the terminal device in an inactive state.

[0156] In this application, there may be multiple implementations for determining that the SDT of a terminal device is completed. In one implementation, the access network device determines that the SDT is completed when it receives a null data packet or a data packet in a preset format. In one implementation, the access network device starts a timer when it receives first uplink information from the terminal device or first downlink data from a second core network device. Here, the timer's time duration is a preset duration. When the timer expires, if the access network device does not receive second uplink information from the terminal device or second downlink data from the second core network device, the access network device determines that the SDT is completed. The first uplink information is uplink information transmitted by the terminal device in the SDT, and the first downlink data is downlink data transmitted by the second core network device in the SDT.

[0157] Step 602: The access network device sends a second message to the first core network device, and in response, the first core network device receives a second message from the access network device.

[0158] In one implementation, the first core network device is an AMF, and the second core network device is a UPF or an SMF.

[0159] Step 603: The first core network device sends a fifth message to the second core network device based on the second message, and in response, the second core network device receives the fifth message from the first core network device.

[0160] The fifth message instructs the second core network device to buffer downlink data of the terminal device, or the fifth message instructs the terminal device to transition to an inactive state. Alternatively, the fifth message is used to distribute new rules to the second core network device. For example, the new rule is to buffer downlink data of the terminal device.

[0161] Implementation 1: When the first core network device is an AMF and the second core network device is an SMF, the AMF may send the fourth message directly to the SMF, and the SMF may further send a response message to the AMF. For example, the response message is a PDU session update session change context response message.

[0162] Implementation 2: If the first core network device is an AMF and the second core network device is a UPF, please refer to the procedure shown in Figure 7.

[0163] Step 701: The AMF sends a fifth message to the SMF. For example, the fifth message is a PDU session update session change context request message.

[0164] In one implementation, the SMF may forward the fifth message to the UPF. In another implementation, the SMF may generate a new message based on the fifth message and forward the generated message to the UPF. An example is shown in step 702.

[0165] Step 702: The SMF sends an N4 session modification message to the UPF based on the fifth message.

[0166] The N4 session modification message instructs the second core network device to buffer downlink data of the terminal device, or the N4 session modification message instructs the terminal device to transition to an inactive state, or the N4 session modification message is used to deliver new rules to the UPF, for example, the new rules are that the UPF buffers downlink data of the terminal device.

[0167] Step 703: The SMF sends a response message to the AMF. For example, the response message is a PDU session update session change context response message.

[0168] In the above procedure, the UPF can buffer downlink data of the terminal equipment when the terminal equipment is in an inactive state.

[0169] Optionally, step 604: The first core network device sends a second response message of the second message to the access network device.

[0170] The second response message is used to confirm that the second core network device buffers the downlink data of the terminal device.

[0171] In one implementation, when the first core network device receives the response message from the second core network device, a second response message may be sent by the first core network device.

[0172] Step 605: The second core network device buffers the downlink data of the terminal device according to the fifth message.

[0173] In one implementation, if there is buffered downlink data that needs to be transmitted to the terminal device within a buffer period, the core network sends a message to the access network through the N2 interface to enable RAN paging. When the terminal device responds to the RAN paging and resumes the RRC connection, the second core network device can transmit the buffered data to the terminal device through the access network. The specific process will not be described again.

[0174] In the above process, when the SDT of the terminal equipment is completed, the access network equipment can activate the second core network equipment to buffer the downlink data of the terminal equipment, so that when the terminal equipment is in an inactive state, the second core network equipment can buffer the downlink data to avoid the terminal equipment in an inactive state being woken up frequently and reduce the power consumption of the terminal equipment.

[0175] Alternatively, in the present application, the core network equipment buffering the downlink data of the terminal equipment may autonomously activate the stopping or halting of the buffering of the downlink data of the terminal equipment, as will be described in detail below.

[0176] 8 is a schematic flowchart illustrating a data transmission method according to an embodiment of the present invention. This method procedure may be performed after the terminal device activates SDT. The method procedure shown in FIG. 8 may be implemented in combination with the method procedure shown in FIG. 6, or may be implemented separately. This is not limited in the present application. The method procedure shown in FIG. 8 may also be implemented in combination with the procedure shown in FIG. 2 or FIG. 3.

[0177] Step 801: The second core network device receives uplink information from the terminal device through the SDT, and sends a buffering release request message to the first core network device.

[0178] The buffer release request message is used to request the terminal equipment to stop or cease buffering downlink data.

[0179] In one implementation, the terminal device starts the SDT before step 801. Before the terminal device starts the SDT, the terminal device is in an inactive state, and the duration of the eDRX period configured by the network side for the terminal device, which is used to monitor RAN paging messages, exceeds 10.24 seconds.

[0180] The second core network device can receive the uplink information of the terminal device through the access network device. The specific process will not be described again.

[0181] Optionally, step 802: the first core network device sends a buffering release response message to the second core network device, and in response, the second core network device receives a buffering release response message from the first core network device, where the buffering release response message is used to respond to the buffering release request message.

[0182] Step 803: The second core network device stops buffering the downlink data of the terminal device, and sends the buffered downlink data to the terminal device through the SDT.

[0183] After sending the buffering release request message or receiving the buffering release response message, the second core network device will no longer buffer the downlink data of the terminal device.

[0184] If the second core network device buffers the downlink data of the terminal device, the second core network device may transmit the buffered downlink data through the SDT. For the specific process, please refer to the above description. The details will not be described again in this specification.

[0185] In the above process, when the terminal device activates the SDT, the access network device can activate the second core network device to stop or halt buffering of the downlink data of the terminal device, so that the second core network device can transmit the downlink data of the terminal device to the terminal device through the SDT. Therefore, when the terminal device is in an inactive state, the terminal device can directly obtain the downlink data without waiting for paging from the network side, thereby improving data transmission efficiency and reducing the power consumption of the terminal device.

[0186] In the above procedure, the first core network device is an AMF, and the second core network device is a UPF or an SMF. If the second core network device is a UPF, the second core network device may send a buffering release request message to the AMF via the SMF. In one implementation, after obtaining the buffering release request message from the UPF, the SMF may forward the buffering release request message to the AMF. In another implementation, the SMF may generate a new message based on the buffering release request message and forward the generated message to the AMF. An example is shown in Figure 9.

[0187] Step 901: The UPF sends a buffering release request message to the SMF.

[0188] Step 902: The SMF sends a PDU session update message to the AMF based on the buffering release request message.

[0189] The PDU session update message indicates that the terminal device should stop or stop buffering downlink data. The PDU session update message may also indicate that all SMFs associated with the terminal device can update the PDU session associated with the terminal device.

[0190] Step 903: The AMF sends a PDU session update confirmation message to the SMF.

[0191] Step 904: The SMF sends a buffering release response message to the UPF.

[0192] In a possible implementation, there may be multiple UPFs. For example, UPF1 buffers downlink data of a terminal device, and UPF2 receives uplink information of the terminal device. In this case, after receiving a buffering release request message, the AMF may instruct UPF1 to stop or discontinue buffering downlink data of the terminal device. For details, please refer to the procedure shown in Figure 5. Details will not be described again in this specification.

[0193] In this application, after the SDT is completed, the core network device that buffers the downlink data of the terminal device may further buffer the downlink data of the terminal device again, in order to avoid the terminal device in an inactive state being frequently woken up. Details will be described below.

[0194] 10 is a schematic flowchart illustrating a data transmission method according to an embodiment of the present invention. The steps of the method illustrated in FIG. 10 may be implemented in combination with the steps of the method illustrated in FIG. 4 or FIG. 8, or may be implemented separately. This is not limited in the present application. The steps of the method illustrated in FIG. 10 may also be implemented in combination with the steps illustrated in FIG. 2 or FIG. 3.

[0195] Step 1001: After determining that the SDT of the terminal device is completed, the second core network device sends a buffering enable request message to the first core network device, where the buffering enable request message is used to request buffering of the downlink data of the terminal device.

[0196] In this application, there may be multiple implementations for determining that the SDT of the terminal device is completed. In one implementation, when the second core network device receives a null data packet or a data packet in a preset format, the second core network device determines that the SDT is completed. In one implementation, when the second core network device receives first uplink information from the terminal device or transmits first downlink data of the terminal device, the second core network device starts a timer. Here, the timer's time duration is a preset duration. When the timer expires, if the second core network device does not receive second uplink information from the terminal device or if there is no second downlink data that needs to be transmitted to the terminal device, the second core network device determines that the SDT is completed.

[0197] Optionally, step 1002: the first core network device sends a buffer validity confirmation message to the second core network device, and in response, the second core network device receives a buffer validity confirmation message from the first core network device.

[0198] Step 1003: The second core network device buffers the downlink data of the terminal device.

[0199] In the above process, when the SDT of the terminal device is completed, if the terminal device is in an inactive state, the second core network device can buffer downlink data to avoid the terminal device in an inactive state being woken up frequently and reduce the power consumption of the terminal device.

[0200] In the above procedure, the first core network device is an AMF, and the second core network device is a UPF or an SMF. If the second core network device is a UPF, the second core network device may send a buffering enable request message to the AMF via the SMF. In one implementation, after obtaining the buffering enable request message from the UPF, the SMF may forward the buffering enable request message to the AMF. In another implementation, the SMF may generate a new message based on the buffering enable request message and forward the generated message to the AMF. An example is shown in Figure 11.

[0201] Step 1101: The UPF sends a buffering enable request message to the SMF.

[0202] Step 1102: The SMF sends a PDU session update message to the AMF based on the buffering enable request message.

[0203] The PDU session update message indicates that the terminal equipment is buffering downlink data. The PDU session update message may further instruct the terminal equipment to transition to an inactive state and indicate that the duration of the eDRX period used by the terminal equipment to monitor RAN paging messages exceeds 10.24 seconds.

[0204] Step 1103: The AMF sends a PDU session update confirmation message to the SMF.

[0205] Step 1104: The SMF sends a buffering release response message to the UPF.

[0206] In a possible implementation, there may be multiple UPFs. For example, UPF1 buffers downlink data of a terminal device, and UPF2 sends a buffering enable request message. In this case, after receiving the buffering enable request message, the AMF may instruct UPF1 to buffer downlink data of the terminal device. For details, please refer to the procedure shown in Figure 7. The details will not be described again in this specification.

[0207] In the above-described embodiments provided in the present application, the methods provided in the embodiments of the present application are described in terms of interactions between devices. To realize the functions in the methods provided in the embodiments of the present application, the access network equipment, the core network equipment, or the terminal equipment may include hardware configurations and / or software modules, and implement the functions in the form of hardware configurations, software modules, or a combination of hardware configurations and software modules. Whether a specific function in the above-described functions is performed by using a hardware configuration, a software module, or a combination of a hardware configuration and a software module depends on the specific application and design constraints of the technical solution.

[0208] In the embodiments of the present application, the module division is an example and is merely a logical division of functions. In actual implementation, other division methods may be used. Furthermore, the functional modules in the embodiments of the present application may be integrated into one processor, or may exist physically alone, or two or more modules may be integrated into one module. The integrated modules may be implemented in the form of hardware or in the form of software functional modules.

[0209] Similar to the above-mentioned concept, as shown in Figure 12, an embodiment of the present application further provides an apparatus 1200 configured to implement the functions of an access network equipment, a core network equipment, or a terminal equipment in the above-mentioned method. For example, the apparatus may be a software module or a chip system. In this embodiment of the present application, the chip system may include a chip, or may include a chip and other individual components. The apparatus 1200 may include a processing unit 1201 and a communication unit 1202.

[0210] In this embodiment of the present application, the communication unit may also be referred to as a transceiver unit and may include a transmitting unit and / or a receiving unit, which are respectively configured to perform the transmitting step and the transceiving step of the access network equipment, the core network equipment, or the terminal equipment in the above-mentioned method embodiments.

[0211] 12 and 13, the communication device provided in the embodiment of the present application will be described in detail below. It should be understood that the description of the device embodiment corresponds to the description of the method embodiment. Therefore, for the contents not described in detail, please refer to the method embodiment. For the sake of brevity, the details will not be described again in this specification.

[0212] The communication unit may also be referred to as a transceiver, a transceiver machine, a transceiver device, or the like. The processing unit may also be referred to as a processor, a processing board, a processing module, a processing unit, or the like. Optionally, components within the communication unit 1202 configured to perform receiving functions may be considered as receiving units, and components within the communication unit 1202 configured to perform transmitting functions may be considered as transmitting units. In other words, the communication unit 1202 includes a receiving unit and a transmitting unit. The receiving unit may also be referred to as a receiving machine, a receiver, a receiving circuit, or the like. The transmitting unit may also be referred to as a transmitting machine, a transmitter, a transmitting circuit, or the like.

[0213] In one implementation, the communications device 1200 may perform the following functions.

[0214] The processing unit is configured to receive uplink information from a terminal device via a communication unit through a small data transmission (SDT), where the resource used for transmitting the uplink information is a random access resource or a configured granted resource used for the SDT.

[0215] The processing unit is configured to: send a first message via the communication unit, where the first message is used to activate the second core network device to stop buffering downlink data of the terminal device; receive downlink data from the second core network device, and send the downlink data to the terminal device through the SDT.

[0216] In one embodiment, the communications device 1200 may perform the following functions.

[0217] The processing unit is configured to receive, via the communication unit, a first message from the access network equipment, where the first message is used to activate the second core network equipment to stop buffering downlink data of the terminal equipment.

[0218] The processing unit is configured to send, via the communication unit, a fourth message to the second core network equipment based on the first message, where the fourth message instructs the second core network equipment to stop buffering downlink data of the terminal equipment, or the fourth message indicates that data transmission can be performed between the terminal equipment and the access network.

[0219] In one implementation, the communications device 1200 may perform the following functions.

[0220] The communication unit is configured to receive a fourth message from the first core network equipment, where the fourth message instructs the second core network equipment to stop buffering downlink data of the terminal equipment, or the fourth message indicates that data transmission can be performed between the terminal equipment and the access network.

[0221] The processing unit is configured to stop buffering of downlink data in the terminal equipment based on the fourth message.

[0222] The communication unit is configured to transmit downlink data of the terminal equipment to the access network equipment.

[0223] In one implementation, the communications device 1200 may perform the following functions.

[0224] The processing unit is configured to: generate a second message after determining that the small data transmission SDT of the terminal device is completed;

[0225] The communication unit is configured to send a second message to the first core network equipment, where the second message is used to activate the second core network equipment to buffer downlink data of the terminal equipment.

[0226] In one implementation, the communications device 1200 may perform the following functions.

[0227] The communication unit is configured to receive a second message from the access network equipment, where the second message is used to activate the second core network equipment to buffer downlink data of the terminal equipment.

[0228] The processing unit is configured to send a fifth message to the second core network device based on the second message, where the fifth message instructs the second core network device to buffer downlink data of the terminal device, or the fifth message instructs the terminal device to transition to an inactive state.

[0229] In one implementation, the communications device 1200 may perform the following functions.

[0230] The communication unit is configured to receive a fifth message from the first core network device, where the fifth message instructs the second core network device to buffer downlink data of the terminal device, or the fifth message instructs the terminal device to transition to an inactive state.

[0231] The processing unit is configured to buffer downlink data of the terminal equipment based on the fifth message.

[0232] In one implementation, the communications device 1200 may perform the following functions.

[0233] The communication unit is configured to: receive uplink information from a terminal device through a small data transmission SDT, and send a buffering release request message to a first core network device, where the buffering release request message is used to request the terminal device to stop buffering downlink data.

[0234] The processing unit is configured to: stop buffering downlink data of the terminal equipment, and send the buffered downlink data to the terminal equipment through the SDT.

[0235] In one implementation, the communications device 1200 may perform the following functions.

[0236] The processing unit is configured to: after determining that the small data transmission SDT of the terminal equipment is completed, send a buffering enable request message to the first core network equipment through the communication unit, where the buffering enable request message is used to request buffering of downlink data of the terminal equipment.

[0237] The communication unit is configured to: receive a buffer release confirmation message from the first core network device, and buffer downlink data of the terminal device. The above is just an example. The processing unit 1201 and the communication unit 1202 may also perform other functions. For more detailed descriptions, please refer to the relevant descriptions in the above-mentioned method embodiments. The details will not be described again in this specification.

[0238] Figure 13 shows an apparatus 1300 according to an embodiment of the present application. The apparatus shown in Figure 13 may be one implementation of the hardware circuit of the apparatus shown in Figure 12. This communication apparatus is applicable to the above-mentioned flowcharts and performs the functions of the access network equipment, core network equipment, or terminal equipment in the above-mentioned method embodiments. For ease of explanation, Figure 13 shows only the main components of the communication apparatus.

[0239] 13, the communication device 1300 includes a processor 1310 and an interface circuit 1320. The processor 1310 and the interface circuit 1320 are coupled to one another. It may be understood that the interface circuit 1320 may be a transceiver or an input / output interface. Optionally, the communication device 1300 may further include a memory 1330 configured to: store instructions to be executed by the processor 1310, store input data required by the processor 1310 to execute the instructions, or store data generated after the processor 1310 executes the instructions.

[0240] When the communication device 1300 is configured to perform the above-described method, the processor 1310 is configured to perform the functions of the processing unit 1201 and the interface circuit 1320 is configured to perform the functions of the communication unit 1202.

[0241] When the communication device is a chip used in an access network equipment, the chip in the access network equipment realizes the function of the access network equipment in the above-mentioned method embodiment. The chip of the access network equipment receives information from another module (such as a radio frequency module or an antenna) in the terminal equipment. Alternatively, the chip of the access network equipment transmits information to another module (such as a radio frequency module or an antenna) in the access network equipment.

[0242] When the communication device is a chip used in a core network equipment, the chip in the core network equipment realizes the function of the core network equipment in the above-mentioned method embodiment. The chip of the core network equipment receives information from another module (e.g., a radio frequency module or an antenna) in the core network equipment. Alternatively, the chip of the core network equipment transmits information to another module (e.g., a radio frequency module or an antenna) in the core network equipment.

[0243] It can be understood that the processor in the embodiments of the present application may be a central processing unit (CPU), or may be another general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. A general-purpose processor may be a microprocessor, any conventional processor, or the like.

[0244] The memory in the embodiments of the present application may be a random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, a hard disk, a removable hard disk, a CD-ROM, or any other form of storage medium known in the art. For example, the storage medium may be coupled to the processor such that the processor can read information from and write information to the storage medium. Indeed, the storage medium may be components of the processor. The processor and the storage medium may be located in an ASIC. Further, the ASIC may be located in a network device or a terminal device. Alternatively, the processor and the storage medium may reside as separate components in the network device or the terminal device.

[0245] Those skilled in the art should understand that the embodiments of the present application may be provided as a method, a system, or a computer program product. As such, the present application may utilize a hardware-only embodiment, a software-only embodiment, or an embodiment combining software and hardware. Furthermore, the present application may utilize the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk memory, optical memory, and the like) containing computer-usable program code.

[0246] The present application has been described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the present application. It should be understood that computer program instructions can be used to implement each process and / or each block in the flowcharts and / or block diagrams, and combinations of processes and / or blocks in the flowcharts and / or block diagrams. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or any other programmable data processing device to generate a machine, whereby the instructions, executed by the processor of the computer or any other programmable data processing device, generate an apparatus for implementing the specific functions in one or more processes in the flowcharts and / or one or more blocks in the block diagrams.

[0247] These computer program instructions may be stored in a computer-readable memory that can instruct a computer or any other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer-readable memory generate a work product that includes an instruction apparatus that implements particular functions within one or more processes in the flowcharts and / or one or more blocks in the block diagrams.

[0248] It is obvious that a person skilled in the art can make various modifications and variations to this application without departing from the scope of this application. This application intends to cover these modifications and variations of this application as long as they fall within the scope of protection defined by the following claims and their equivalent technologies.

Claims

1. 1. A data transmission method, comprising: receiving uplink information from a terminal device through a small data transmission (SDT), wherein a resource used for transmitting the uplink information is a random access resource or a configured granted resource used for the SDT; sending a first message, the first message being used to activate a second core network device to stop buffering downlink data of the terminal equipment; receiving downlink data from the second core network device and transmitting the downlink data to the terminal device through the SDT; A method comprising:

2. The method of claim 1 , wherein the device that sends the first message is an access network device that maintains a context for the terminal device.

3. obtaining a context of the terminal device; The method of claim 1 further comprising:

4. transmitting a second message after the step of determining that the SDT is completed, the second message being used to activate the second core network device to buffer the downlink data of the terminal device, or the second message indicating a period duration of an extended discontinuous reception period for monitoring paging messages initiated by a radio access network by the terminal device in an inactive state. The method of any one of claims 1 to 3, further comprising:

5. The step of determining that the SDT is complete comprises: determining that the SDT is complete upon receiving a null data packet or a data packet of a preset format; The method of claim 4, comprising:

6. The step of determining that the SDT is complete comprises: Upon receiving first uplink information from the terminal device or first downlink data from the second core network device, starting a timer, wherein the timer has a time duration that is a preset period; determining that the SDT is completed if the timer expires and no second uplink information is received from the terminal device or no second downlink data is received from the second core network device; The method of claim 4, comprising:

7. Sending a third message to the terminal device, the third message instructing the terminal device to transition to an inactive state. The method of claim 4 further comprising:

8. Releasing the terminal device to the inactive state; maintaining, for the terminal device, the context of the terminal device and a connection to a first core network device associated with the terminal device; The method of any one of claims 1 to 7, further comprising:

9. 8. The method according to claim 1, wherein the device that transmits the first message is an access network device to which a cell belongs, to which the terminal device is currently camped.

10. receiving a first response message to the first message, the first response message being used to confirm that the second core network equipment is activated to stop or halt buffering of downlink data of the terminal equipment, or the first response message being used to confirm that data transmission can be performed between the terminal equipment and the access network; The method of any one of claims 1 to 9, further comprising:

11. transmitting a sixth message, the sixth message being used to activate the second core network device to start buffering downlink data of the terminal equipment; The method of any one of claims 1 to 9, further comprising:

12. A data transmission method, receiving a first message from an access network device, the first message being used to activate a second core network device to stop buffering downlink data of the terminal device; sending a fourth message to the second core network device based on the first message, the fourth message instructing the second core network device to stop buffering the downlink data of the terminal device, or the fourth message indicating that data transmission can be performed between the terminal device and an access network; A method comprising:

13. receiving a sixth message from the access network equipment, the sixth message being used to activate the second core network equipment to start buffering the downlink data of the terminal equipment; sending a seventh message to the second core network equipment based on the sixth message, the seventh message instructing the second core network equipment to start buffering the downlink data of the terminal equipment, or the seventh message indicating that data transmission cannot be performed between the terminal equipment and the access network; The method of claim 12 further comprising:

14. A data transmission method, receiving a fourth message from a first core network device, the fourth message instructing a second core network device to stop buffering downlink data of the terminal device, or the fourth message indicating that data transmission can be performed between the terminal device and an access network; stopping buffering of the downlink data of the terminal equipment based on the fourth message, and transmitting the downlink data of the terminal equipment to an access network equipment; A method comprising:

15. The method of claim 14 , wherein the access network equipment is a device that maintains the context of the terminal equipment.

16. 15. The method of claim 14, further comprising: receiving a seventh message from the first core network equipment, the seventh message indicating to start buffering the downlink data of the terminal equipment, or the seventh message indicating that data transmission cannot be performed between the terminal equipment and the access network.

17. 1. A data transmission method, comprising: generating a second message after the step of determining that the small data transmission SDT of the terminal device is completed; sending the second message to a first core network device, the second message being used to activate the second core network device to buffer downlink data of the terminal device; A method comprising:

18. The step of determining that the small data transmission SDT of the terminal device is completed includes: determining that the SDT is complete upon receiving a null data packet or a data packet in a preset format; 18. The method of claim 17, comprising:

19. The step of determining that the small data transmission SDT of the terminal device is completed includes: Upon receiving first uplink information from the terminal device or first downlink data from the second core network device, starting a timer, wherein the timer has a preset duration; determining that the SDT is completed if the timer expires and no second uplink information is received from the terminal device or no second downlink data is received from the second core network device; 18. The method of claim 17, comprising:

20. sending a third message to the terminal device, the third message instructing the terminal device to transition to an inactive state; 20. The method of any one of claims 17 to 19, further comprising:

21. 20. The method of any one of claims 17 to 19, further comprising the step of maintaining the terminal device context.

22. 1. A data transmission method, comprising: receiving a second message from the access network equipment, the second message being used to activate a second core network equipment to buffer downlink data of the terminal equipment; sending a fifth message to the second core network device based on the second message, the fifth message instructing the second core network device to buffer the downlink data of the terminal device, or the fifth message instructing the terminal device to transition to an inactive state; A method comprising:

23. 1. A data transmission method, comprising: receiving a fifth message from a first core network device, the fifth message instructing the second core network device to buffer downlink data for the terminal device, or the fifth message instructing the terminal device to transition to an inactive state; buffering the downlink data in the terminal device based on the fifth message; A method comprising:

24. 1. A data transmission method, comprising: receiving uplink information from a terminal device through a small data transmission (SDT), and sending a buffering release request message to a first core network device, the buffering release request message being used to request the terminal device to stop buffering downlink data; stopping buffering of the downlink data in the terminal device and transmitting the buffered downlink data to the terminal device through the SDT; A method comprising:

25. receiving a buffering release response message from the first core network device, the buffering release response message being used to respond to the buffering release request message; 25. The method of claim 24, further comprising:

26. buffering the downlink data in the terminal device after the step of determining that the SDT is completed.

26. The method of claim 24 or 25, further comprising:

27. sending a buffering enable request message to the first core network device, the buffering enable request message indicating a request to buffer the downlink data of the terminal device; 27. The method of claim 26, further comprising:

28. The step of determining that the SDT is complete comprises: determining that the SDT is complete upon receiving a null data packet or a data packet in a preset format; 27. The method of claim 26, comprising:

29. The step of determining that the SDT is complete comprises: upon receiving first uplink information from the terminal device, starting a timer, the timer having a time duration that is a preset duration; determining that the SDT is complete if no second uplink information is received from the terminal device when the timer expires; 27. The method of claim 26, comprising:

30. 1. A data transmission method, comprising: After determining that the small data transmission (SDT) of the terminal device is completed, sending a buffering enable request message to a first core network device, the buffering enable request message being used to request buffering of downlink data of the terminal device; receiving a buffering release acknowledgement message from the first core network device, and buffering the downlink data of the terminal device; A method comprising:

31. The step of determining that the SDT of the terminal device is completed comprises: determining that the SDT is complete upon receiving a null data packet or a data packet in a preset format; 31. The method of claim 30, comprising:

32. The step of determining that the SDT of the terminal device is completed comprises: upon receiving first uplink information from the terminal device, starting a timer, the timer having a time duration that is a preset duration; determining that the SDT is complete if no second uplink information is received from the terminal device when the timer expires; 31. The method of claim 30, comprising:

33. A communication device, a processing unit configured to receive uplink information from a terminal device through a small data transmission (SDT) via a communication unit, wherein resources used for transmitting the uplink information are random access resources or configured granted resources used for the SDT; Equipped with the processing unit is configured to: send a first message via the communication unit, the first message being used to activate a second core network device to stop buffering downlink data of the terminal device; receive downlink data from the second core network device; and transmit the downlink data to the terminal device through the SDT. Device.

34. 34. The apparatus of claim 33, wherein the communication device is an access network device that maintains a context for the terminal device.

35. The communication device Obtaining the context of the terminal device 34. The apparatus of claim 33 configured to:

36. The communication unit After determining that the SDT is completed, transmitting a second message, the second message being used to activate the second core network device to buffer the downlink data of the terminal device, or the second message indicating a period duration of an extended discontinuous reception period for monitoring a paging message initiated by a radio access network by the terminal device in an inactive state.

36. The apparatus of any one of claims 33 to 35, further configured to:

37. The processing unit determining that the SDT is complete when a null data packet is received or a data packet in a preset format is received; 37. The apparatus of claim 36, specifically configured to:

38. The processing unit Upon receiving first uplink information from the terminal device or receiving first downlink data from the second core network device, starting a timer, wherein the timer has a time duration that is a preset duration; determining that the SDT is completed when the timer expires and no second uplink information is received from the terminal device or no second downlink data is received from the second core network device; 37. The apparatus of claim 36, specifically configured to:

39. The processing unit sending a third message to the terminal device, the third message indicating that the terminal device will transition to the inactive state; 37. The apparatus of claim 36, specifically configured to:

40. The processing unit Releasing the terminal device to the inactive state and retaining, for the terminal device, the context of the terminal device and a connection to a first core network device associated with the terminal device.

40. Apparatus according to any one of claims 33 to 39, specifically adapted to:

41. 40. The apparatus according to any one of claims 33 to 39, wherein the communication device is an access network device to which a cell belongs, to which the terminal device is currently camped.

42. The communication device receiving a first response message to the first message, wherein the first response message is used to confirm that the second core network device is activated to stop or halt buffering of the downlink data of the terminal device, or the first response message is used to confirm that data transmission can be performed between the terminal device and the access network; 42. The apparatus of any one of claims 33 to 41, further configured to:

43. The communication unit sending a sixth message, the sixth message being used to activate the second core network device to start buffering downlink data of the terminal device; 42. The apparatus of any one of claims 33 to 41, further configured to:

44. A communication device, a processing unit configured to receive a first message from an access network equipment via a communication unit, the first message being used to activate a second core network equipment to stop buffering downlink data of a terminal equipment; Equipped with the processing unit is configured to send a fourth message to the second core network equipment via the communication unit based on the first message, the fourth message instructing the second core network equipment to stop buffering the downlink data of the terminal equipment, or the fourth message indicating that data transmission can be performed between the terminal equipment and the access network. Device.

45. The communication unit receiving a sixth message from the access network equipment, the sixth message being used to activate the second core network equipment to start buffering the downlink data of the terminal equipment; sending a seventh message to the second core network equipment based on the sixth message, the seventh message instructing the second core network equipment to start buffering the downlink data of the terminal equipment, or the seventh message indicating that data transmission cannot be performed between the terminal equipment and the access network; 45. The apparatus of claim 44, further configured to:

46. A communication device, a communication unit configured to receive a fourth message from a first core network device, the fourth message instructing a second core network device to stop buffering downlink data of a terminal device, or the fourth message indicating that data transmission can be performed between the terminal device and an access network; and a processing unit configured to stop buffering of the downlink data in the terminal device based on the fourth message; Equipped with The communication unit is configured to transmit the downlink data of the terminal equipment to an access network equipment; Device.

47. The apparatus of claim 46, wherein the access network equipment is an apparatus that maintains a context of the terminal equipment.

48. The communication unit receiving a seventh message from the first core network device, the seventh message indicating that the terminal device should start buffering the downlink data, or the seventh message indicating that data transmission cannot be performed between the terminal device and the access network; 47. The apparatus of claim 46, further configured to:

49. A communication device, a processing unit configured to generate a second message after determining that the small data transmission SDT of the terminal device is completed; a communication unit configured to send a second message to a first core network device, the second message being used to activate a second core network device to buffer downlink data of the terminal device; An apparatus comprising:

50. The processing unit determining that the SDT is complete when a null data packet is received or a data packet in a preset format is received; 50. The apparatus of claim 49, specifically configured to:

51. The processing unit Upon receiving first uplink information from the terminal device or receiving first downlink data from the second core network device, starting a timer, wherein the timer has a preset duration; determining that the SDT is completed when the timer expires and no second uplink information is received from the terminal device or no second downlink data is received from the second core network device; 50. The apparatus of claim 49, specifically configured to:

52. The communication unit sending a third message to the terminal device, the third message instructing the terminal device to transition to an inactive state; 52. The apparatus of any one of claims 49 to 51, further configured to:

53. 53. Apparatus according to any one of claims 49 to 52, wherein the communication unit is configured to maintain a context of the terminal equipment.

54. A communication device, a communication unit configured to receive a second message from an access network equipment, the second message being used to activate a second core network equipment to buffer downlink data of a terminal equipment; and a processing unit configured to send a fifth message to the second core network device based on the second message, the fifth message instructing the second core network device to buffer the downlink data of the terminal device, or the fifth message instructing the terminal device to transition to an inactive state; An apparatus comprising:

55. A communication device, a communication unit configured to receive a fifth message from a first core network device, the fifth message instructing a second core network device to buffer downlink data of a terminal device, or the fifth message instructing the terminal device to transition to an inactive state; a processing unit configured to buffer the downlink data of the terminal device based on the fifth message; An apparatus comprising:

56. A communication device, a communication unit configured to receive uplink information from a terminal device through a small data transmission (SDT) and send a buffering release request message to a first core network device, the buffering release request message being used to request the terminal device to stop buffering downlink data; a processing unit configured to stop buffering of the downlink data in the terminal device and transmit the buffered downlink data to the terminal device through the SDT; An apparatus comprising:

57. The communication unit receiving a buffering release response message from the first core network device, the buffering release response message being used to respond to the buffering release request message; 57. The apparatus of claim 56, further configured to:

58. The processing unit After determining that the SDT is completed, buffering the downlink data in the terminal device.

58. The apparatus of claim 56 or 57, further configured to:

59. The communication unit sending a buffering enable request message to the first core network device, the buffering enable request message indicating a request to buffer the downlink data of the terminal device; 59. The apparatus of claim 58, further configured to:

60. The processing unit determining that the SDT is complete when a null data packet is received or a data packet in a preset format is received; 59. The apparatus of claim 58, specifically configured to:

61. The processing unit Upon receiving first uplink information from the terminal device, starting a timer, the timer having a preset time; determining that the SDT is completed if no second uplink information is received from the terminal device when the timer expires; 59. The apparatus of claim 58, specifically configured to:

62. A communication device, a processing unit configured to send a buffering enable request message to a first core network device through a communication unit after determining that a small data transmission (SDT) of a terminal device is completed, the buffering enable request message being used to request buffering of downlink data of the terminal device; Equipped with The communication unit is configured to receive a buffer release confirmation message from the first core network device and buffer the downlink data of the terminal device. Device.

63. The processing unit determining that the SDT is complete when a null data packet is received or a data packet in a preset format is received; 63. The apparatus of claim 62, specifically configured to:

64. The processing unit Upon receiving first uplink information from the terminal device, starting a timer, the timer having a preset time; determining that the SDT is completed if no second uplink information is received from the terminal device when the timer expires; 63. The apparatus of claim 62, specifically configured to:

65. A communication device comprising a processor and a memory, The processor is configured to execute computer programs or instructions stored in the memory, and when the processor executes the computer programs or instructions, the method of any one of claims 1 to 32 is performed. Device.

66. 33. A chip comprising a processor, the processor coupled to a memory and configured to execute computer programs or instructions stored in the memory, wherein execution of the computer programs or instructions by the processor performs the method of any one of claims 1 to 32.

67. 33. A computer readable storage medium storing instructions which, when executed on a computer, enable the computer to carry out a method according to any one of claims 1 to 32.

68. 33. A computer program product storing computer readable instructions which, when read and executed by a communications device, enable the communications device to perform a method according to any one of claims 1 to 32.

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